Plug insert bit for core drills



March 6, 1951 H. J. MADER PLUG INSERT BIT FOR CORE DRILLS Filed Feb. 12, 1948 INVENTOR ATTORNEYS Patented Mar. 6, 1 951 UNITED STATES PATENT- OFFICE PLUG INSERT BIT FOR CORE DRILLS Harry J. Mader, Jerome, Ariz.

Application February 12, 1948, Serial No. 7,811

This invention relates to improvements in plug insert bits for core drills.

An object of the invention is to provide an improved plug insert bit for use with core drills.

Another object of the invention is to provide a detachable plug insert bit for use with core drills and having a flat face in which diamonds 1 Claim. (Cl. 25573) or other cuttin stones or materials are embedded.

A further object of the invention is provide an improved replaceable plug insert bit for use with core drills, the same having a fiat face in which diamonds or other cutting stones or materials are embedded, and having oppositely disposed longitudinally extending water grooves formed therein.

A still further object of the invention is to provide an improved plug insert bit for use with core drills, the same bein supported by a cross pin in retracted position to produce a concave type bit or in advanced position to produce a pilot type bit.

Another object of the invention is to provide an improved plug insert bit having a flat cutting surface in which diamonds or other cuttin stones or materials are embedded, said bit being highly efficient in operation and relatively inexpensive to manufacture and produce.

Other objects will appear as the description proceeds.

In the accompanying drawings which form a part of this application, I

Figure 1 is a bottom view of a core drill bit with the improved plug insert bit supported therein in advance of the core drill bit to produce a pilot type bit.

Fig. 2 is a sectional view taken on the line 2-2 of Fig.1.

Fig. 3 is a bottom view of a core drill bit with the improved plug insert bit supported therein in retracted position to produce a concave type bit.

Fig. 4 is a sectional view taken on the line 44 of Fig. 3.

Like characters of reference are used throughout the following specification and the accompanying drawings to designate corresponding parts.

In carryin out the invention, there is shown and provided a core drill bit I having an upwardly extending reduced portion 2 which is externally threaded as at 3 for connection with the usual drill rod (not shown). Diamonds or other cutting stones or materials 4 are embedded in the lower annular end 5 of the core drill bit I.

The improved plug insert bit 6 is of a size to fit snugly within the core drill bit I, with the lower end of the insert bit 6 extending in advance of or below the lower end of said core drill bit The flat lower face I of the insert bit 6 will support diamonds or other cutting stones or materials 3 which also are disposed a slight way up the side of the insert bit 6.

Oppositely disposed parallel Water grooves 9 and H! are formed longitudinally in the plug insert bit 6, and are angled inwardly as at I l and I2 adjacent their lower ends to discharge through the face 1 of the insert bit 6.

Aligned transversely extending bores l3 and I4 will be formed through the core drill bit I and the plu insert bit 6, and will receive the cross pin 15 for securin said plug insert bit 6 within the core drill bit I. The ends of the pin l5 will be caulked in or otherwise secured. Diametrically opposed water grooves I6 will be formed across the cutting end 5 of the core drill bit I.

In Figs. 3 and 4, a similar core drill bit I is provided, the same being reduced on the upper end 2 and externally threaded as at 3, and having diametrically opposed water grooves l6 formed across the cutting end 5 in which the diamonds 4 or other cutting stones or materials are embedded.

The plug insert bit 6 is supported in retracted position within the core drill bit I by mean of the cross pin l5 which is inserted through the aligned bores I3 and I4 through the core drill bit I and the plug insert bit 6. Diamonds 8 or other cutting stones or materials are embedded in the lower face 7 of the plug insert bit 6 to provide a concave type bit.

Oppositely disposed parallel water grooves 9 and ID are formed in the plug insert bit 6 and extend straight down to discharge through the face 1 of the plug insert bit 6.

From the foregoing description, it will be seen thatin the event the plug insertbit 6 wears out before the core drill l, a new plug insert bit 6 may replace the worn out one, and vice versa,

should the core drill bit I wear out first, a new Having thus described my invention, what I claim as new and desire to secure by Letters'Patent of the United States is:

A drilling tool, comprising a tubular member having a reduced threaded portion adjacent to the drilling end thereof providing an enlarged drillin end having a diamond embedded cutting surface, an insert bit fitted within the tubular member in close engagement therewith, said bit having a diamond embedded cutting end extended beyond the cutting surface of the tubular member, said tubular member and bit having aligning transversely disposed openings, a cross pin permanently secured in the aligning openings securing the bit Within the tubular member, and said bit having longitudinally extended water grooves providing discharge passageways, the discharge ends of the grooves being directed inwardly towards each other.

HARRY J. MADER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 58,924 Webster Oct. 16, 1866 1,746,455 Woodruff et a1. Feb. 11, 1930 1,878,292 Pivoto Sept. 20, 1932 1,940,996 Carr Dec. 26, 1933 2,053,801 Mitchell Sept. 8, 1936 2,056,319 Harrington Oct. 6, 1936 2,081,302 Jarvis May 25, 1937 2,256,092 Koebel et al Sept. 16, 1941 FOREIGN PATENTS Number Country Date 5,942 Great Britain Sept. 1, 1910 472,587 Great Britain Sept. 27, 1937 

